A risk-free rate is required when computing the Sharpe Ratio. Morningstar uses the 3-month T-bill as the risk-free investment. However, there are not daily returns for the 3-month T-bill. If you select Daily as your return frequency, you will need to find a substitution here.
Click the Type arrow to select the type of your preferred equivalent.
Choose the radio button labeled with the method you are going to use to find the equivalent (which may include Name, Ticker, or Policy). If searching by name or policy, choose either Begins with or Contains.
Enter name or ticker in the Find box. Click Go. Matches will appear in the Available Records box.
Highlight the desired equivalent and click OK. Your selection will be populated in the T-Bill Equivalent box on the Point to Point Returns screen.